With respect to recognition and long term memories, corticosterone has variable effects. Studies show that the modification of certain chemical and brain processes that affect corticosterone levels can also impact stress effects on memory. In studies on rats, the fluctuations of corticosterone concentration are shown to prevent stress’ impairment of recognition memory in lower amounts. These lower levels seem to be linked to the rescue of stress-induced attenuation of CA1 long-term potentiation . [10] When researchers looked at stress effects on LTM, they found many outcomes. In multiple studies, the formation of LTM (tested 24 h later) was found to be enhanced by corticosterone in some studies, while the persistence of LTM (tested at least 1 wk later) was only assisted by corticosterone in the late phase of memory consolidation and reconsolidation . [11] [12] Stress facilitates the consolidation but disrupts the reconsolidation of emotional memory. As mentioned previously, the persistence of LTM is selectively enhanced when stress and corticosterone are administered during the late phase after acquisition, but it is disrupted when stress and corticosterone are administered during the late phase after retrieval of memory. [12] With regards to the persistence of LTM, there is a restricted time window between acquisition or retrieval where persistence is affected. These studies found that while persistence of LTM is selectively affected based on stage of memory, the formation of LTM is left intact after a certain length of time. Up to this point, studies have not agreed as to whether or not these processes are dependent on corticosterone or what even happens based on corticosterone in these processes and how memory is ultimately affected.